Radiation detecting apparatus, radiographic image capturing system, and radiographic image capturing method

ABSTRACT

An electronic cassette in a radiographic image capturing system includes a radiation detector for detecting radiation applied from an image capturing apparatus and transmitted through a patient, a contactless power receiver for receiving electric power supplied contactlessly from a power feeder and supplying the electric power to a battery, an A/D converter for performing an A/D conversion to convert analog radiographic image information generated based on the radiation applied to the radiation detector into digital radiographic image information, an end-of-A/D-conversion determining unit for determining whether the A/D conversion is finished or not, and a charging controller for stopping the power feeder from supplying electric power contactlessly after the image capturing apparatus has started capturing images until the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Patent Applications No. 2008-316529 filed on Dec. 12, 2008 and No. 2009-271507 filed on Nov. 30, 2009, in the Japan Patent Office, of which the contents are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radiation detecting apparatus having a radiation detector for detecting radiation which has passed through a subject and a contactless power receiver, a radiographic image capturing system having a contactless power feeder for contactlessly supplying electric power to such a radiation detecting apparatus, and a radiographic image capturing method.

2. Description of the Related Art

In the medical field, there have widely been used radiographic image capturing apparatus, which apply radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel, which captures a radiographic image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiographic image by way of exposure, and a stimulable phosphor panel for storing radiation energy representing a radiographic image in a phosphor and reproducing the radiographic image as stimulated light by applying stimulating light to the phosphor. The radiation film with the recorded radiographic image is supplied to a developing device to develop the radiographic image, or the stimulable phosphor panel is supplied to a reading device to read the radiographic image as a visible image.

In the operating room or the like, it is necessary to read and display a recorded radiographic image immediately from a radiation conversion panel after the radiographic image has been captured for the purpose of quickly and appropriately treating the patient. Patients such as infants, children, aged people, or those who cannot stand themselves for a long time due to illness or injuries also need to be imaged quickly. As a radiation conversion panel which meets such a requirement, there has been developed a radiation detector having a solid-state detector for converting radiation directly into electric signals or converting radiation into visible light with a scintillator and then converting the visible light into electric signals to read a detected radiographic image.

Japanese Laid-Open Patent Publication No. 2008-170315 discloses a radiation detecting apparatus (electronic cassette) having a function to transmit radiographic image information produced by a radiation detector to an image processor or the like via a wireless transmission system. The electronic cassette incorporates a battery therein. For charging the battery, the electronic cassette is mounted on a separate cradle having a contactless battery charger. The battery is contactlessly (wirelessly) charged by the contactless battery charger while the electronic cassette is being mounted on the cradle.

According to the radiation detecting apparatus disclosed in Japanese Laid-Open Patent Publication No. 2008-170315, when the remaining power level of the battery runs low after the radiation detecting apparatus has been used to capture a plurality of radiographic images of a patient during a surgical operation on the patient, it is necessary to remove the electronic cassette from under the patient, bring the electronic cassette to the cradle, and charge the battery in the electronic cassette that is mounted on the cradle. However, such a charging process is troublesome and possibly tends to make the surgical operation time-consuming and be burdensome to the patient.

Another problem is that if the battery is contactlessly charged by the contactless battery charger while radiographic image information produced by a radiation detector incorporated in the electronic cassette is being converted from an analog signal to a digital signal during the surgical operation, noise caused by magnetic fluxes used for the contactless power charging is liable to adversely affect the radiographic image information, particularly the analog signal prior to being converted into the digital signal. As a result, it is highly possible for the radiation detecting apparatus to fail to acquire high-quality radiographic images.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a radiation detecting apparatus, a radiographic image capturing system, and a radiographic image capturing method which make it possible to supply electric power to the radiation detecting apparatus with ease and also to acquire high-quality radiographic images.

A radiation detecting apparatus according to the present invention comprises a radiation detector for detecting radiation applied from an external image capturing apparatus and transmitted through a subject, a contactless power receiver for receiving electric power supplied contactlessly from an external contactless power feeder and supplying the received electric power to a power supply, an A/D converter for performing an A/D conversion to convert analog radiographic image information which has been generated based on the radiation applied to the radiation detector, into digital radiographic image information, an end-of-A/D-conversion determining unit for determining whether the A/D conversion is finished or not, and a charging controller for stopping the contactless power feeder from supplying electric power contactlessly after the external image capturing apparatus has started to capture a radiographic image until the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.

A radiographic image capturing system according to the present invention comprises an image capturing apparatus for applying radiation to a subject, a radiation detecting apparatus including a radiation detector for detecting the radiation transmitted through the subject, an A/D converter for performing an A/D conversion to convert analog radiographic image information which has been generated based on the radiation applied to the radiation detector, into digital radiographic image information, and a power supply for supplying electric power to the radiation detector, a contactless power feeder disposed in the radiation detecting apparatus, for supplying electric power contactlessly to a contactless power receiver which supplies electric power to the power supply, a controller for controlling the image capturing apparatus, the radiation detecting apparatus, and the contactless power feeder, an end-of-A/D-conversion determining unit for determining whether the A/D conversion is finished or not, and a charging controller for stopping the contactless power feeder from supplying electric power contactlessly after the image capturing apparatus has started to capture a radiographic image until the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.

With the above arrangement, while the radiation detecting apparatus with the radiation detector for detecting the radiation, e.g., an electronic cassette, is being held in a given image capturing position, the contactless power feeder can supply electric power to the radiation detecting apparatus with ease. Additionally, the end-of-A/D-conversion determining unit and the charging controller are provided, and after the image capturing apparatus has started capturing a radiographic image of the subject until the A/D conversion is finished, the contactless power feeder stops supplying electric power contactlessly to the contactless power receiver. Therefore, since the contactless power feeding is inhibited from the start of image-capturing at least until the conversion of the analog radiographic image information detected by the radiation detector into the digital radiographic image information is completed, the analog radiographic image information which is susceptible to noise is prevented from being adversely affected by noise which is caused by the contactless power feeding from the contactless power feeder. Thus, it is possible to acquire radiation images of high quality. After the A/D conversion, i.e., at a time when the radiographic image information is relatively less susceptible to noise, the radiographic image capturing system can quickly start supplying electric power to the power supply. Even when the remaining power level of the power supply has been greatly reduced by a previous image capturing process, the power supply can be quickly charged after the previous image capturing process and made ready for a next image capturing process.

In order to reliably stop the contactless power feeder from supplying electric power contactlessly to the contactless power receiver from the start of image capturing until the end of the A/D conversion, the charging controller may generate a feeding inhibition signal to inhibit the contactless power feeder from supplying electric power contactlessly before the external image capturing apparatus starts to capture a radiographic image, or the charging controller may generate a feeding permission signal to permit the contactless power feeder to supply electric power contactlessly if the end-of-A/D-conversion determining unit judges that the A/D conversion is finished

The radiation detecting apparatus may further comprise an image memory for storing the digital radiographic image information converted by the A/D converter, and the end-of-A/D-conversion determining unit may judge that the A/D conversion is finished when the digital radiographic image information is stored in the image memory. With this arrangement, the radiographic image information is effectively prevented from being adversely affected by noise while it is being transferred to the image memory, and hence from being corrupted. Consequently, the radiographic image capturing system can acquire radiographic images of high quality.

There may be further provided an image capturing controller for generating an image capturing permission signal to permit the image capturing apparatus to capture a radiographic image of the subject when the charging controller generates the feeding inhibition signal. The image capturing controller makes it possible to more reliably inhibit the contactless power feeder from supplying electric power contactlessly during the image capturing process.

The radiographic image capturing system may be connected to an information management system for storing the number of times that the subject is to be imaged, and the end-of-A/D-conversion determining unit may determine whether the A/D conversion is finished or not after as many radiographic images of the subject as the number of times that the subject is to be imaged which is stored in the information management system have been captured. With this arrangement, the contactless power feeder can start supplying electric power contactlessly reliably after all the radiographic images of the subject have been captured and the A/D conversion of all the radiographic image information is completed.

The charging controller may generate the feeding permission signal when the image capturing apparatus stops applying the radiation and when the end-of-A/D-conversion determining unit judges that the A/D conversion is finished. With this arrangement, even if information about the number of times that the subject is to be imaged cannot be obtained from a network or the like, the end of the capturing of the desired number of radiographic images can be judged from the stop of the application of the radiation, e.g., the turning-off of an image capturing switch. Accordingly, the radiographic image capturing system can start supplying electric power contactlessly to the power supply reliably after the capturing of all radiographic images and the A/D conversion of all radiographic image information are completed.

The charging controller may generate the feeding permission signal upon elapse of a given time after the end-of-A/D-conversion determining unit has judged that the A/D conversion is finished. With this arrangement, the completion of the A/D conversion and the time required for the transfer of the digital radiographic image information to the image memory can be secured, and noise is effectively prevented from adversely affecting the digital radiographic image information being transferred to the image memory.

The charging controller may generate the feeding permission signal upon elapse of a given time after the image capturing apparatus has started applying the radiation. With this arrangement, the time from the start of the application of the radiation until the completion of the A/D conversion and the time required for the transfer of the digital radiographic image information to the image memory can be secured, and thereafter the feeding permission signal can be generated. The end-of-A/D-conversion determining unit may judge that the A/D conversion has been finished in view of the given time from the start of the application of the radiation. In other words, the function of the end-of-A/D-conversion determining unit may be integrated into the charging controller.

According to the present invention, there is also provided a method of capturing a radiographic image of a subject by applying radiation to the subject, detecting the radiation with a radiation detector of a radiation detecting apparatus, and converting the detected radiation into radiographic image information with the radiation detector, comprising the steps of supplying electric power contactlessly to a power supply of the radiation detecting apparatus, and stopping supplying electric power contactlessly to the power supply after image-capturing by the radiation has been started at least until an A/D conversion of the radiographic image information detected by the radiation detector is finished.

The above method is effective to prevent noise generated by electric power supplied contactlessly from a contactless power feeder from adversely affecting captured radiographic images by starting to supply electric power contactlessly at least after the completion of the A/D conversion of the acquired radiographic image information. Therefore, it is possible to acquire radiographic images of high quality.

The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an operating room incorporating a radiographic image capturing system according to a first embodiment of the present invention;

FIG. 2 is a perspective view, partly cut away, showing internal structural details of an electronic cassette used in the radiographic image capturing system shown in FIG. 1;

FIG. 3 is a block diagram of a circuit arrangement of a radiation detector in the electronic cassette shown in FIG. 2;

FIG. 4 is a block diagram of the radiographic image capturing system shown in FIG. 1;

FIG. 5 is a block diagram of the radiographic image capturing system, showing structural details of the electronic cassette shown in FIG. 4;

FIG. 6 is a flowchart of an image capturing, sequence of the radiographic image capturing system shown in FIG. 4;

FIG. 7 is a block diagram of a radiographic image capturing system according to a second embodiment of the present invention;

FIG. 8 is a flowchart of a first image capturing sequence of the radiographic image capturing system shown in FIG. 7;

FIG. 9 is a flowchart of a second image capturing sequence of the radiographic image capturing system shown in FIG. 7;

FIG. 10 is a flowchart of a third image capturing sequence of the radiographic image capturing system shown in FIG. 7;

FIG. 11 is a block diagram of a radiographic image capturing system according to a first modification of the radiographic image capturing system shown in FIG. 4;

FIG. 12 is a perspective view of another electronic cassette;

FIG. 13 is a perspective view of a cradle for charging a battery in the electronic cassette;

FIG. 14 is a side elevational view, partly in block form, of a radiographic image capturing system according to a second modification of the radiographic image capturing system shown in FIG. 4;

FIG. 15 is a side elevational view, partly in block form and cross section, of a radiographic image capturing system according to a third modification of the radiographic image capturing system shown in FIG. 4;

FIG. 16 is a schematic view of a radiographic image capturing system according to a fourth modification of the radiographic image capturing system shown in FIG. 4; and

FIG. 17 is a schematic view of a radiographic image capturing system according to a fifth modification of the radiographic image capturing system shown in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Like or corresponding parts are denoted by like or corresponding reference characters throughout views.

Radiographic image capturing systems and radiographic image capturing methods according to preferred embodiments of the present invention, in reference to radiation detecting apparatus used in the radiographic image capturing systems, will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, an operating room 12 houses therein a radiographic image capturing system 10 (hereinafter also referred to as “image capturing system 10”) according to a first embodiment of the present invention. The operating room 12 houses, in addition to the radiographic image capturing system 10, a surgical table or bed 16 for a patient 14 to lie thereon, and an instrument table 20 disposed on one side of the surgical table 16 for placing thereon various tools and instruments to be used by a surgeon 18 for operating the patient 14. The surgical table 16 is surrounded by various apparatus required for surgical operations, including an anesthesia apparatus, an aspirator, an electrocardiograph, a blood pressure monitor, etc (not shown).

The image capturing system 10 includes an image capturing apparatus (radiation applying apparatus) 22 for irradiating the patient 14 as a subject with radiation X at a dose according to image capturing conditions, an electronic cassette (radiation detecting apparatus) 24 housing therein a radiation detector 40 (see FIG. 2) for detecting the radiation X that has passed through the patient 14, a power feeder (contactless power feeder, wireless power feeder) 25 for supplying electric power wirelessly (contactlessly) to a battery 44 (see FIG. 2) housed in the electronic cassette 24, a display device 26 for displaying a radiographic image based on the radiation X that has been detected by the radiation detector 40, and a console (controller) 28 for generally controlling the image capturing system 10. The image capturing apparatus 22, the electronic cassette 24, the power feeder 25, the display device 26, and the console 28 send and receive signals by way of UWB (Ultra Wide Band) wireless communications indicated by the broken lines.

Since the power feeder 25 and the electronic cassette 24 are out of contact with each other, a contactless power feeding technique for feeding power contactlessly (wirelessly) is adopted as a technique for feeding power to (the battery 44 of) the electronic cassette 24 by the power feeder 25, as described above.

Specifically, the contactless power feeding technique includes (1) a microwave power feeding technique in which the power feeder 25 feeds power to the electronic cassette 24 using an electromagnetic wave in the microwave band, (2) an electromagnetic induction power feeding technique in which the power feeder 25 feeds power to the electronic cassette 24 by electromagnetic induction with the coil of the power feeder 25 being in proximity to the coil of the electronic cassette 24, and (3) a resonance power feeding technique in which the power feeder 25 feeds power to the electronic cassette 24 using electromagnetic resonance between the power feeder 25 and the electronic cassette 24.

Also, the above resonance power feeding technique (3) includes a magnetic resonance power feeding technique. In the magnetic resonance power feeding technique, the coils of the power feeder 25 and the electronic cassette 24 are adjusted to have substantially the same resonant frequency, and the coil of the power feeder 25 on the sending side generates electromagnetic field caused by high-frequency electric power in a given space of the operating room 12, while the coil of the electronic cassette 24 on the receiving side is placed in the generated electromagnetic field, whereby the coil of the electronic cassette 24 can receive the high-frequency electric power.

Incidentally, the contactless power feeding technique for feeding power to the electronic cassette 24 by the power feeder 25 (microwave type, electromagnetic induction type, resonance type, magnetic resonance type) can adopt a conventional contactless power feeding technique.

Hereinafter, if not otherwise specified, the power feeder 25 feeds power to the battery 44 of the electronic cassette 24 using a magnetic resonance power feeding technique.

The image capturing apparatus 22 is coupled to a universal arm 30 extending from the ceiling of the operating room 12 so as to be movable to a desired position for capturing an image of a desired area of the patient 14 and also to be retractable to a position out of the way while the surgeon 18 is performing a surgical operation on the patient 14. Similarly, the power feeder 25 is coupled to a universal arm 31 so as to be movable to a desired position depending on the location of the electronic cassette 24. The display device 26 is coupled to a universal arm 32 so as to be movable to a position where the surgeon 18 can easily confirm a captured radiographic image displayed on the display device 26. The universal arms 30, 31, 32 may alternatively be mounted on a wall, a floor, or a movable cart. The power feeder 25 and the display device 26 may alternatively be fixed to the ceiling, a wall, or a floor rather than being supported on the universal arms. The power feeder 25 should preferably be positioned horizontally laterally of the radiation detecting apparatus (the electronic cassette 24) (see FIGS. 1 and 14) or on the bottom side of the radiation detecting apparatus (see FIG. 15) so that a magnetic field M (electromagnetic field due to high-frequency electric power) applied from the power feeder 25 to the radiation detecting apparatus will be kept out of direct interference with the patient 14.

FIG. 2 shows in perspective internal structural details of the electronic cassette 24. As shown in FIG. 2, the electronic cassette 24 has a box-shaped casing 34 made of a material permeable to the radiation X. The casing 34 houses therein a grid 38 for removing scattered rays of the radiation X from the patient 14, a radiation detector (radiation conversion panel) 40 for detecting the radiation X that has passed through the patient 14, and a lead plate 42 for absorbing back scattered rays of the radiation X, which are successively arranged in the order named from a surface 36 of the casing 34 which is irradiated with the radiation X. The irradiated surface 36 of the casing 34 may be constructed as the grid 38.

The casing 34 also houses therein a battery 44 serving as a power supply of the electronic cassette 24, a cassette controller 46 for energizing the radiation detector 40 with electric power supplied from the battery 44, and a transceiver 48 for sending and receiving signals including the information of the radiation X (radiographic image information) detected by the radiation detector 40, to and from the console 28 by wireless communications. A shield plate of lead or the like should preferably be placed over the side surfaces of the battery 44, the cassette controller 46, and the transceiver 48 under the irradiated surface 36 of the casing 34 to protect the battery 44, the cassette controller 46, and the transceiver 48 against damage which would otherwise be caused if irradiated with the radiation X. The casing 34 also houses therein a wireless power receiver (contactless power receiver) 49 for receiving the magnetic field (magnetic fluxes) M converted from electric energy (high-frequency electric power) and applied contactlessly (wirelessly) by the power feeder 25, and converting the magnetic field M back into electric energy.

FIG. 3 shows in block form a circuit arrangement of the radiation detector 40. As shown in FIG. 3, the radiation detector 40 comprises an array of thin-film transistors (TFTs) 52 arranged in rows and columns, a photoelectric conversion layer 51 made of a material such as amorphous selenium (a-Se) for generating electric charges upon detection of the radiation X, the photoelectric conversion layer 51 being disposed over the array of TFTs 52, and an array of storage capacitors (storage devices) 53 connected to the photoelectric conversion layer 51. When the radiation X is applied to the radiation detector 40, the photoelectric conversion layer 51 generates electric charges, and the storage capacitors 53 store the generated electric charges. Then, the TFTs 52 are turned on along each row at a time to read the electric charges from the storage capacitors 53 as an image signal. In FIG. 3, the photoelectric conversion layer 51 and one of the storage capacitors 53 are shown as a pixel 50, and the pixel 50 is connected to one of the TFTs 52. Details of the other pixels 50 are omitted from illustration. Since amorphous selenium tends to change its structure and lose its function at high temperatures, it needs to be used within a certain temperature range. Therefore, some means for cooling the radiation detector 40 should preferably be provided in the electronic cassette 24.

The TFTs 52 connected to the respective pixels 50 are connected to respective gate lines 54 extending parallel to the rows and respective signal lines 56 extending parallel to the columns. The gate lines 54 are connected to a line scanning driver 58, and the signal lines 56 are connected to a multiplexer 66 serving as a reading circuit.

The gate lines 54 are supplied with control signals Von, Voff for turning on and off the TFTs 52 along the rows from the line scanning driver 58. The line scanning driver 58 comprises a plurality of switches SW1 for switching between the gate lines 54 and an address decoder 60 for outputting a selection signal for selecting one of the switches SW1 at a time. The address decoder 60 is supplied with an address signal from the cassette controller 46.

The signal lines 56 are supplied with electric charges stored in the storage capacitors 53 of the pixels 50 through the TFTs 52 arranged in the columns. The electric charges supplied to the signal lines 56 are amplified by amplifiers 62 connected respectively to the signal lines 56. The amplifiers 62 are connected through respective sample and hold circuits 64 to the multiplexer 66. The multiplexer 66 comprises a plurality of switches SW2 for successively switching between the signal lines 56 and an address decoder 68 for outputting a selection signal for selecting one of the switches SW2 at a time. The address decoder 68 is supplied with an address signal from the cassette controller 46. The multiplexer 66 has an output terminal connected to an A/D converter 70. A radiographic image signal generated by the multiplexer 66 based on the electric charges from the sample and hold circuits 64 is converted by the A/D converter 70 into a digital image signal representing radiographic image information, which is supplied to the cassette controller 46.

The TFTs 52 which function as switching devices may be combined with another image capturing device such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor or the like. Alternatively, the TFTs 52 may be replaced with a CCD (Charge-Coupled Device) image sensor for shifting and transferring electric charges with shift pulses which correspond to gate signals in the TFTs.

FIG. 4 shows in block form the image capturing system 10 which comprises the image capturing apparatus 22, the electronic cassette 24, the power feeder 25, the display device 26, and the console 28.

The console 28 is connected to a radiology information system (RIS, information management system) 29 which stores and generally manages radiographic image information handled by the radiological department of the hospital and other information, e.g., ordering information representative of the number of times that the patient 14 is to be imaged (the number of radiographic images thereof to be captured, the number of times that the patient 14 is to be exposed to the radiation X). Also, the RIS 29 is connected to a hospital information system (HIS) 33 which generally manages medical information in the hospital. Alternatively, the console 28 may be connected to a consolidated system which combines the functions of the HIS 33 and the RIS 29.

The image capturing apparatus 22 comprises an image capturing switch 72, a radiation source 74, a transceiver 76, and a radiation source controller 78. The transceiver 76 receives image capturing conditions from the console 28 by way of wireless communications and transmits an image capturing completion signal, etc. to the console 28 by way of wireless communications. The radiation source controller 78 controls the radiation source 74 based on an image capturing start signal supplied from the image capturing switch 72 and image capturing conditions supplied from the console 28. The radiation source 74 outputs the radiation X under the control of the radiation source controller 78.

The power feeder 25 comprises a power supply 80 connected to an external power supply or the like, not shown, a transceiver 82 for receiving a power feeding start signal, etc. from the console 28 by way of wireless communications and sending ID information (ID data), etc. of the power feeder 25 to the console 28 by way of wireless communications, an LC resonator (feeding unit) 84 for converting electric energy from the power supply 80 into the magnetic field M and applying the magnetic field M, or in other words, contactlessly (wirelessly) supplying electric energy, to the electronic cassette 24, and a power feeding controller 86 for energizing the LC resonator 84 based on the power feeding start signal supplied from the console 28.

FIG. 5 shows in block form the image capturing system 10, showing structural details of the electronic cassette 24 as the radiation detecting apparatus according to the present embodiment.

As shown in FIGS. 4 and 5, the electronic cassette 24 includes the radiation detector 40, the battery 44, the wireless power receiver 49, the cassette controller 46, and the transceiver 48.

The battery 44 comprises a chargeable secondary battery such as a lithium ion battery or the like, and serves as a power supply for supplying electric power to various parts of the electronic cassette 24, which include the radiation detector 40, the cassette controller 46, and the transceiver 48. The battery 44 may alternatively comprise an electric storage device such as an electric double layer capacitor or any of other devices insofar as it can be charged and serve as a power supply for the electronic cassette 24.

The wireless power receiver 49 has a function to receive the electric power contactlessly (wirelessly) supplied from the power feeder 25 and supply the received electric power to the battery 44, i.e., charge the battery 44 with the received electric power. The wireless power receiver 49 has an LC resonator 88 for receiving the magnetic field M applied from the LC resonator 84 of the power feeder 25 into electric energy (high-frequency power), and a charging circuit 90 for converting the electric energy from the LC resonator 88 into desired electric power and supplying the electric power to the battery 44. Specifically, the LC resonator 88 comprises an LC resonant circuit having a coil and a capacitor, and the charging circuit 90 rectifies the electric current generated by the LC resonator 88 into a constant electric current, and charges the battery 44 with the constant electric current.

The wireless power receiver 49 also has a detecting LC resonator 94 disposed parallel to the LC resonator 88 and smaller in size than the LC resonator 88, and an energy detector 96 for detecting electric energy converted from the magnetic field M by the detecting LC resonator 94. The detecting LC resonator 94 also comprises an LC resonant circuit having a coil and a capacitor, as with the LC resonator 88. When the energy detector 96 detects the electric energy converted from the magnetic field M by the detecting LC resonator 94, the energy detector 96 detects that the electronic cassette 24 is positioned within a feeding area of the power feeder 25, and sends a feeding area detection signal to the cassette controller 46.

Each of the LC resonators 84, 88, 94 has an LC resonance circuit comprising a coil and a capacitor. The power feeder 25 can contactlessly (wirelessly) supply electric power to the electronic cassette 24 according to the known power transmission technology which utilizes the resonance of the magnetic field M (magnetic resonance) from the LC resonator 84 to the LC resonator 88.

As shown in FIG. 5, the cassette controller 46 comprises an address signal generator 98, an image memory 100, an operation manager 102, a cassette ID memory 104, and a data manager 106. The address signal generator 98 supplies address signals to the address decoder 60 of the line scanning driver 58 of the radiation detector 40 and the address decoder 68 of the multiplexer 66 of the radiation detector 40. The image memory 100 stores radiographic image information detected by the radiation detector 40. Specifically, the image memory 100 stores radiographic image information generated by the radiation detector 40 when the radiation X is applied to the radiation detector 40 and converted into electric charges, and the electric charges are stored and then read and converted into digital signals.

The operation manager 102 controls operation of the wireless power receiver 49 and the battery 44, and also controls overall operation of the electronic cassette 24. The operation manager 102 comprises an end-of-A/D-conversion determining unit 107, a charging controller 108, and an image capturing controller 109.

The end-of-A/D-conversion determining unit 107 determines whether the A/D conversion of radiographic image information by the A/D converter 70 is ended or not. The charging controller 108 generates a signal (feeding inhibition signal or charging inhibition signal) for inhibiting the power feeder 25 from feeding the electronic cassette 24, i.e., for inhibiting the electronic cassette 24 from being charged by the power feeder 25, before the image capturing apparatus 22 starts capturing a radiographic image, and generates a signal (feeding permission signal or charging permission signal) for permitting the power feeder 25 to feed the electronic cassette 24, i.e., for permitting the electronic cassette 24 to be charged by the power feeder 25, when the end-of-A/D-conversion determining unit 107 judges that the A/D conversion of radiographic image information by the A/D converter 70 is ended. The charging controller 108 may be configured as a plurality of controllers (signal generators) for generating the respective signals. The image capturing controller 109 generates control signals (image capturing permission signal and image capturing inhibition signal) for permitting the image capturing apparatus 22 to capture a radiographic image and inhibiting the image capturing apparatus 22 from capturing a radiographic image.

The feeding inhibition signal and the feeding permission signal which are generated by the charging controller 108 and the image capturing permission signal and the image capturing inhibition signal which are generated by the image capturing controller 109 are transmitted from the transceiver 48 to the console 28. When the console 28 receives these signals, the console 28 performs a control process for inhibiting (stopping) the contactless power feeding (wireless power feeding) from the power feeder 25 and a control process for starting (resuming) the contactless power feeding (wireless power feeding) from the power feeder 25, and also performs a control process for permitting (starting) the image capturing by the image capturing apparatus 22 and a control process for inhibiting (stopping) the image capturing by the image capturing apparatus 22. Alternatively, the electronic cassette 24 may directly transmit the feeding inhibition (permission) signal and the image capturing permission (inhibition) signal to the power feeder 25, not through the console 28, and the power feeding controller 86 and the radiation source controller 78 may perform the control process for inhibiting (starting) the contactless power feeding (wireless power feeding) and the control process for starting (inhibiting) the image capturing.

The cassette ID memory 104 stores cassette ID information for identifying the electronic cassette 24. The data manager 106 manages ID information (ID data) for identifying the power feeder 25 which feeds the electronic cassette 24 and a feeding area detection signal from the energy detector 96.

The transceiver 48 receives a transmission request signal from the console 28 and the ID information of the power feeder 25 by way of wireless communications, and transmits the radiographic image information, the cassette ID information, a wireless feeding enable signal, the feeding inhibition signal, the feeding permission signal, the image capturing permission signal, the image capturing inhibition signal, etc. to the console 28.

As shown in FIG. 4, the display device 26 comprises a receiver 110 for receiving the radiographic image information from the console 28, a display controller 112 for processing the received radiographic image information, and a display unit 114 for displaying the radiographic image information processed by the display controller 112.

The console 28 comprises a transceiver 116, an image capturing condition manager 118, an image processor 120, an image memory 122, a patient information manager 124, a cassette information manager 126, and a power feeding information manager 128. The console 28 may be located outside of the operating room 12 insofar as it can reliably transmit and receive signals to and from the image capturing apparatus 22, the electronic cassette 24, the power feeder 25, and the display device 26.

The transceiver 116 of the console 28 transmits and receives necessary information including radiographic image information, the feeding inhibition (permission) signal, and the image capturing permission (inhibition) signal to and from the image capturing apparatus 22, the electronic cassette 24, the power feeder 25, and the display device 26 by way of wireless communications. The image capturing condition manager 118 manages image capturing conditions required for the image capturing apparatus 22 to capture radiographic images, and also performs the control process for starting the image capturing by the image capturing apparatus 22 and the control process for inhibiting the image capturing by the image capturing apparatus 22 based on the image capturing permission signal and the image capturing inhibition signal from the image capturing controller 109. The image processor 120 processes radiographic image information transmitted from the electronic cassette 24. The image memory 122 stores the radiographic image information processed by the image processor 120. The patient information manager 124 manages patient information of the patient 14 whose images are to be captured. The cassette information manager 126 manages the wireless feeding enable signal and the cassette information including the cassette ID information transmitted from the electronic cassette 24. The power feeding information manager 128 manages the operation control of the power feeder 25 and ID information sent from the power feeder 25, and also performs the control process for inhibiting the power feeding by the power feeder 25 and the control process for starting (resuming) the power feeding by the power feeder 25 based on the feeding inhibition signal and the feeding permission signal from the charging controller 108.

The image capturing conditions refer to conditions for determining a tube voltage, a tube current, an irradiation time, etc. required to apply radiation X at an appropriate dose to an area to be imaged of the patient 14. The image capturing conditions may include an area to be imaged of the patient 14, an image capturing method, etc., for example. The image capturing conditions may also include conditions representing the number of times that a radiographic image is to be captured, as ordering information from the RIS 29, for example. The patient information refers to information for identifying the patient 14, such as the name, gender, patient ID number, etc. of the patient 14. Ordering information for instructing the image capturing system 10 to capture a radiation image, including the image capturing conditions and the patient information, can be set directly on the console 28 or can be supplied from an external source to the console 28 via the RIS 29. The cassette information includes the wireless feeding enable signal from the data manager 106 in addition to the cassette ID information for identifying the electronic cassette 24.

The image capturing system 10 according to the first embodiment is basically constructed as described above, and operation of the image capturing system 10 will be described below with reference to a flowchart shown in FIG. 6.

The image capturing system 10 is installed in the operating room 12 and used when radiographic images of the patient 14 are required by the surgeon 18 who is performing a surgical operation on the patient 14. Before radiographic images of the patient 14 are captured, patient information of the patient 14 to be imaged and the number of radiographic images to be captured are registered in the patient information manager 124 of the console 28. If an area to be imaged of the patient 14 and an image capturing method have already been known, they are registered beforehand as image capturing conditions in the image capturing condition manager 118. These information and conditions can be registered by being acquired from the RIS 29. After the above preparatory process is finished, the surgeon 18 performs a surgical operation on the patient 14.

In step S1 shown in FIG. 6, for capturing radiographic images of the patient 14 during the surgical operation, the surgeon 18 or a radiological technician working on the image capturing system 10 places the electronic cassette 24 in a desired position between the patient 14 and the surgical table 16 with the irradiated surface 36 facing the image capturing apparatus 22.

At the same time that the console 28 starts to operate or when the surgeon 18 or the radiological technician turns on an operation start switch, not shown, the power feeder 25 is energized under given operating conditions (a low output operation mode). The electronic cassette 24 is now detected as being placed within the feeding area of the power feeder 25 by the detecting LC resonator 94 and the energy detector 96 of the wireless power receiver 49. Specifically, the energy detector 96 functions as a power feeding enable/disable detector for detecting whether the electronic cassette 24 is placed within the feeding area of the power feeder 25 or not. At this time, the power feeding controller 86 of the power feeder 25 operates in the low output operation mode for applying, from the LC resonator 84, a relatively weak magnetic field M which can be detected by the detecting LC resonator 94 and the energy detector 96 of the wireless power receiver 49. Therefore, the power consumption of the power feeder 25 is kept at a low level.

In the electronic cassette 24, the energy detector 96 supplies a feeding area detection signal to the data manager 106. In response to the feeding area detection signal, the data manager 106 receives the ID information of the power feeder 25 which is stored in the power feeding information manager 128 from the console 28, and transmits the wireless feeding enable signal to the cassette information manager 126 of the console 28.

The energy detector 96 also supplies the feeding area detection signal to the operation manager 102. In response to the feeding area detection signal, the operation manager 102 turns on the electronic cassette 24 to make it ready for use, thereby completing preparations for image capturing. Of course, the electronic cassette 24 may have, for example, on a side thereof, a power supply switch, not shown, which can be operated by the surgeon 18 or the radiological technician.

After the preparations for image capturing have been completed, the cassette controller 46 or the cassette information manager 126 of the console 28 manages the remaining power level of the battery 44 to determine whether the remaining power level is sufficient or not, i.e., whether the battery 44 needs to be charged or not, in step S2. If it is judged that the battery 44 needs to be charged (“NO” in step S2), then the cassette information manager 126 sends a power feeding start signal to the power feeding controller 86 of the power feeder 25. The power feeder 25 now supplies electric power to the electronic cassette 24, i.e., charges the battery 44 of the electronic cassette 24 with a desired amount of electric power at a desired timing in step S3. If the remaining power level of the battery 44 runs low during the surgical operation, then the battery 44 may be charged while it is being kept in the given image capturing position. If the remaining power level of the battery 44 runs low during the preparations for image capturing, i.e., while the electronic cassette 24 is being placed in position, or before radiographic images start being captured, then the battery 44 can be charged in a contactless (wireless) fashion immediately before or after the surgical operation is started, so that the preparations for image capturing can be completed quickly.

For contactlessly (wirelessly) supplying electric power to the electronic cassette 24, the power feeder 25 may be energized to apply the magnetic field M from the LC resonator 84 to the electronic cassette 24 under given operating conditions for a stronger level than in the low output operation mode (high output operation mode, power feeding operation mode). In the electronic cassette 24, the energy received by the detecting LC resonator 94 as well as the energy received by the LC resonator 88, may be used to charge the battery 44 through the charging circuit 90, for thereby quickly charging the battery 44.

The image capturing system 10 allows the console 28 to confirm the ID information of the power feeder 25 that is associated with the electronic cassette 24. Accordingly, even if the image capturing system 10 includes a plurality of power feeders that are selectively usable, the electronic cassette 24 can be appropriately and selectively supplied with electric power from a desired selected one of the power feeders based on the ID information confirmed by the console 28. As a result, wasteful power consumption and erroneous operation can be avoided.

If it is judged that the remaining power level of the battery 44 is sufficient (“YES” in step S2), then the charging controller 108 transmits a feeding inhibition signal (step S4), and the image capturing controller 109 transmits an image capturing permission signal (step S5). Therefore, the power feeder 25 is brought into a feeding inhibition state and the image capturing apparatus 22 is brought into an image capturing start standby state capable of capturing radiographic images under the control of the console 28 (the image capturing condition manager 118 and the power feeding information manager 128). Consequently, while a radiographic image is being captured, the electronic cassette 24 is prevented from being contactlessly (wirelessly) supplied with electric power. Therefore, the voltage supplied from the battery 44 to the radiation detector 40 is prevented from becoming unstable and fluctuating greatly, and noise caused by the magnetic field M applied from the power feeder 25 is prevented from adversely affecting the radiation detector 40, so that a captured radiographic image is effectively prevented from suffering from noise and decreasing in quality.

In step S6, the surgeon 18 or the radiological technician moves the image capturing apparatus 22 to a position facing the electronic cassette 24, and then turns on the image capturing switch 72 to capture a radiographic image of the patient 14. The image capturing switch 72 comprises a two-stage switch including first and second stages, for example. The first stage starts up the radiation source 74 at a given tube current, and then the second stage operates the radiation source 74 to emit the radiation X.

When the surgeon 18 or the radiological technician operates the image capturing switch 72, the radiation source controller 78 of the image capturing apparatus 22 sends a request to the console 28 for sending the image capturing conditions. Based on the received request, the console 28 sends the image capturing conditions for an area to be imaged of the patient 14 which are registered in the image capturing condition manager 118 and the number of radiographic images to be captured, to the image capturing apparatus 22. When the radiation source controller 78 receives the image capturing conditions, it controls the radiation source 74 to apply radiation X at a given dose to the patient 14 according to the image capturing conditions. The image capturing conditions may be sent in advance from the console 28 to a memory, not shown, in the radiation source controller 78.

The radiation X which has passed through the patient 14 is applied to the grid 38, which removes scattered rays of the radiation X. Then, the radiation X is applied to the radiation detector 40, and converted into electric signals by the photoelectric conversion layer 51 of the pixels 50 of the radiation detector 40. The electric signals are stored as electric charges in the storage capacitors 53 (see FIG. 3). The stored electric charges (signal charges), which represent radiographic image information of the patient 14, are read from the storage capacitors 53 according to address signals which are supplied from the address signal generator 98 of the cassette controller 46 to the line scanning driver 58 and the multiplexer 66.

Specifically, in response to the address signal supplied from the address signal generator 98, the address decoder 60 of the line scanning driver 58 outputs a selection signal to select one of the switches SW1, which supplies the control signal Von to the gates of the TFTs 52 connected to the gate line 54 corresponding to the selected switch SW1. In response to the address signal supplied from the address signal generator 98, the address decoder 68 of the multiplexer 66 outputs a selection signal that successively turns the switches SW2 on in order to switch between the signal lines 56, for thereby reading the electric charges stored in the storage capacitors 53 of the pixels 50 connected to the selected gate line 54, through the signal lines 56.

The electric charges read from the storage capacitors 53 of the pixels 50 connected to the selected gate line 54 are amplified by the respective amplifiers 62, sampled by the sample and hold circuits 64, and supplied to the multiplexer 66. Based on the supplied electric charges, the multiplexer 66 generates and supplies a radiographic image signal to the A/D converter 70, which converts the radiographic image signal into a digital signal (step S7). The digital signal which represents the radiographic image information is stored in the image memory 100 of the cassette controller 46.

Similarly, the address decoder 60 of the line scanning driver 58 successively turns on the switches SW1 to switch between the gate lines 54 according to the address signal supplied from the address signal generator 98. The electric charges stored in the storage capacitors 53 of the pixels 50 connected to the successively selected gate lines 54 are read through the signal lines 56, and processed by the multiplexer 66 and the A/D converter 70 into digital signals (step S7), which are stored in the image memory 100 of the cassette controller 46.

The radiographic image information represented by the digital signals stored in the image memory 100 is transmitted to the console 28 by way of wireless communications. The radiographic image information transmitted to the console 28 is received by the transceiver 116, processed by the image processor 120, and then stored in the image memory 122 in association with the patient information of the patient 14 registered in the patient information manager 124.

The radiographic image information processed by the image processor 120 is transmitted from the console 28 to the display device 26. In the display device 26, the receiver 110 receives the radiographic image information, and the display controller 112 controls the display unit 114 to display a radiographic image based on the radiation image information. The surgeon 18 can perform the surgical operation on the patient 14 while visually confirming the radiographic image displayed on the display unit 114.

Even if the remaining power level of the battery 44 of the electronic cassette 24 runs low due to a plurality of radiographic images captured during the surgical operation, since the electronic cassette 24 is contactlessly (wirelessly) supplied with electric power from the power feeder 25, the battery 44 of the electronic cassette 24 can be charged with the electronic cassette 24 being kept in the image capturing position. While radiographic images are being captured, particularly until the A/D conversion of the electric charges is finished, since the radiographic image information is represented by an analog signal, it tends to be greatly affected by noise caused by the contactless (wireless) power feeding, and the captured radiographic image is liable to contain the noise. Consequently, the image capturing system 10 is highly likely to fail to acquire radiographic images of high quality.

The image capturing system 10 according to the present embodiment is arranged to overcome the above difficulties as follows: The image capturing system 10 includes the end-of-A/D-conversion determining unit 107, the charging controller 108, and the image capturing controller 109, which operate to inhibit the contactless (wireless) power feeding at least until the conversion of the analog radiographic image information detected by the radiation detector 40 into digital signals is completed.

Specifically, when the image capturing system 10 starts to prepare itself for capturing radiographic images, e.g., when the surgeon 18 or the radiological technician turns on the image capturing switch 72 or the radiation source controller 78 of the image capturing apparatus 22 sends a request to the console 28 for sending the image capturing conditions, the console 28 sends an image capturing start signal to the electronic cassette 24 to operate the cassette controller 46, thereby completing preparations for capturing radiographic images in the electronic cassette 24, at the same time that or before the console 28 controls the image capturing apparatus 22 (steps S1, S2). At the same time, in the electronic cassette 24, the charging controller 108 generates a feeding inhibition signal to inhibit the power feeder 25 from supplying electric power to the electronic cassette 24, and the image capturing controller 109 generates an image capturing permission signal to make the image capturing apparatus 22 ready for capturing radiographic images (steps S4, S5).

When the image capturing system 10 starts to capture a radiographic image (step S6), the radiographic image information detected by the radiation detector 40 is converted from analog signals into digital signals by the A/D converter 70 (step S7). The application of the radiation X and the A/D conversion of the detected radiographic image information are performed until a preset number of radiographic images are captured, i.e., until the radiation X is applied to the subject 14 by a preset number of times (step S8).

When the preset number of radiographic images have been captured (“YES” in step S8), the end-of-A/D-conversion determining unit 107 determines whether the A/D conversion immediately after the number of radiographic images have been captured is finished or not (step S9). If the end-of-A/D-conversion determining unit 107 judges that the A/D conversion is finished, i.e., if the end-of-A/D-conversion determining unit 107 judges that all the radiographic image information produced in the present image capturing process has been converted into digital signals (“YES” in step S9), then the charging controller 108 generates a feeding permission signal in step S10.

The feeding permission signal is transmitted from the electronic cassette 24 to the console 28. The power feeding information manager 128 manages the operation control of the power feeder 25 to perform the control process for starting the power feeding by the power feeder 25, or the control process for bringing the power feeder 25 into a power feeding start standby state (power feeding resumption standby state) to allow the power feeder 25 to start the power feeding immediately (step S12). When the A/D conversion of all the acquired radiographic image information is finished after the preset number of radiographic images have been captured, therefore, electric power can quickly be supplied contactlessly (wirelessly) to the battery 44 (step S13). If the control process for bringing the power feeder 25 into the power feeding start standby state is carried out, then after the console 28 has received the feeding permission signal, the cassette controller 46 or the cassette information manager 126 checks the remaining power level of the battery 44 (step S11), and then the control process for starting the power feeding is performed. The feeding permission signal may be directly sent from the electronic cassette 24 to the power feeder 25, not through the console 28, and the power feeding controller 86 and the cassette controller 46 may perform the control process for starting the power feeding and the control process for bringing the power feeder 25 into the power feeding start standby state.

The end-of-A/D-conversion determining unit 107 may preferably determine whether the A/D conversion is finished or not (step S9) based on whether a period (storage period) in which the radiation X that has passed through the patient 14 is applied to the radiation detector 40 and converted into electric signals by the photoelectric conversion layer 51 of the pixels 50, and the electric signals are stored as signal charges in the storage capacitors 53, a period (readout period) in which the electric charges stored in the storage capacitors 53 are read, and a period (A/D conversion period) in which the read electric charges (analog signal) are converted into digital signals by the A/D converter 70 have elapsed or not. In these three periods, added noise tends to adversely affect the image signal (radiographic image information) significantly. Specifically, in the storage period and the readout period, added noise tends to adversely affect the electric charges significantly because the electric charges are low in level. In the A/D conversion period, the analog signal is less resistant to noise than the digital signal, and noise added to the analog signal is likely to be converted into a digital signal and appear in the image data.

The storage period includes a time in which the radiation source 74 applies the radiation X. After the storage capacitors 53 have started to store electric charges, the radiation source 74 should start applying the radiation X as quickly as possible. Then, the electric charges stored in the storage capacitors 53 should start being read out immediately after the radiation source 74 has stopped applying the radiation X. If any time lags of these operations are minimized, then a so-called dark current is reduced so as to further improve the quality of the acquired radiographic image. The readout period referred to above is a period in which the TFTs 52 are turned on to send signals through the amplifiers 62 to the A/D converter 70. The readout period and the A/D conversion period are essentially synchronous with each other. Practically, however, the readout period starts slightly earlier than the A/D conversion period.

The end-of-A/D-conversion determining unit 107 should preferably determine whether the A/D conversion is finished or not (step S9) based on whether the storage of the digital signals representative of the radiographic image information in the image memory 100 is finished after the A/D conversion period. In this case, during data transfer to the image memory 100, during which data may be susceptible to noise though not as significantly as during the A/D conversion, the data are effectively prevented from being adversely affected by noise which may be caused by the contactless (wireless) electric power transmission from the power feeder 25 to the electronic cassette 24, and hence from being corrupted. Alternatively, the time at which the transmission of the image data from the image memory 100 via the transceivers 48, 116 is completed may be judged as the time at which the A/D conversion is finished, so that the image data will be more effectively prevented from being adversely affected by noise which may be caused by the contactless (wireless) electric power transmission.

The feeding permission signal may be generated in step S10 at any desired timing after the A/D conversion (step S9), e.g., after the transmission of the digital signals from the electronic cassette 24 to the console 28 is completed.

As described above, even though the feeding inhibition signal is generated (step S4) to inhibit the power feeding during the capture of a radiographic image, the image capturing system 10 can quickly start (resume) supplying electric power to the battery 44 after the A/D conversion has been finished (steps S10 through S13), i.e., at a time when the radiographic image information is relatively less susceptible to noise. This is particularly effective when the battery 44 needs to be quickly charged for the next image capturing process after the remaining power level thereof has been greatly reduced in the previous image capturing process. If another image capturing process is to be performed after the sequence of steps S1 through S13, then control may return from step S13 or S11 to step S1.

The image capturing system 10 may be configured to charge the battery 44 under the control of the console 28 at desired times other than when radiographic images are captured.

As described above, with the image capturing system 10 according to the present embodiment, even though the electronic cassette 24 is placed in a desired image capturing position with respect to the patient 14, the power feeder 25 can easily supply electronic power to the electronic cassette 24. Even if the battery 44 of the electronic cassette 24 needs to be charged during the surgical operation, the battery 44 can be charged without the need for moving the electronic cassette 24. Accordingly, the electronic cassette 24 and the image capturing system 10 can be handled with ease as a whole. Furthermore, the process of capturing a radiographic image and the surgical operation are effectively prevented from being interrupted and prolonged due to a low remaining power level of the battery 44 of the electronic cassette 24.

The image capturing system 10 (the electronic cassette 24) has the end-of-A/D-conversion determining unit 107, the charging controller 108, and the image capturing controller 109, and a feeding inhibition signal is generated before the image capturing system 10 starts to capture a radiographic image, and a feeding permission signal is generated after the A/D conversion of radiographic image information is ended. As the contactless (wireless) power feeding is inhibited at least until the conversion of the analog radiographic image information detected by the radiation detector 40 into digital signals is completed, the analog radiographic image information that is susceptible to noise is prevented from being adversely affected by noise caused by the contactless (wireless) power feeding from the power feeder 25. Therefore, it is possible to acquire radiographic images of high quality. Since the image capturing controller 109 generates an image capturing permission signal when the charging controller 108 generates a feeding inhibition signal, the contactless (wireless) power feeding from the power feeder 25 is more reliably inhibited during the image capturing process.

After the A/D conversion, i.e., at a time when radiographic image information is relatively less susceptible to noise, the power feeder 25 quickly starts (resumes) the power feeding in response to a feeding permission signal from the charging controller 108. Therefore, even if the remaining power level of the battery 44 is greatly lowered by an image capturing process, the battery 44 can quickly be charged after the image capturing process and made ready for a next image capturing process.

When the electronic cassette 24 is placed within the feeding area of the power feeder 25, the electronic cassette 24 and the power feeder 25 automatically exchanges information with each other through the console 28, and the electronic cassette 24 is automatically brought into a state capable of capturing a radiographic image. Consequently, the electronic cassette 24 is not required to have a manual power supply switch, and the surgeon 18 or the radiological technician is prevented from making a mistake not to capture a radiographic image by forgetting to operating such a manual power supply switch. Accordingly, the electronic cassette 24 and the image capturing system 10 can be handled with greater ease as a whole. If the energy detector 96 of the electronic cassette 24 does not detect the desired magnetic field M, then the data manager 106 may send a wireless feeding disable signal, for example, to the cassette information manager 126, from which the wireless feeding disable signal is sent to the display device 26 for indicating to the surgeon 18 or the radiological technician that it is not possible to supply electric power from the power feeder 25 to the electronic cassette 24, on the display unit 114.

FIG. 7 is a block diagram of a radiographic image capturing system 10 a according to a second embodiment of the present invention.

As shown in FIG. 7, the radiographic image capturing system 10 a according to the second embodiment is basically the same as the radiographic image capturing system 10 (see FIGS. 4 and 5) according to the first embodiment except that the RIS 29 and the HIS 33 are not connected to the console 28. However, the radiographic image capturing system 10 a according to the second embodiment is different from the radiographic image capturing system 10 according to the first embodiment as to an image capturing process, particularly a control process for contactless (wireless) power feeding. Specifically, the radiographic image capturing system 10 a performs first through third image capturing sequences shown in FIGS. 8 through 10. The radiographic image capturing system 10 a is preferably used as a radiographic image capturing system that is not connected to the RIS 29 and the HIS 33, e.g., a radiographic image capturing system in a hospital which is free of the RIS 29 and the HIS 33 or a radiographic image capturing system to accompany a doctor when going the rounds in a hospital.

The first image capturing sequence of the radiographic image capturing system 10 a will first be described below with reference to FIG. 8. Those control steps shown in FIG. 8 which are denoted by the same step numbers as those shown in FIG. 6 represent the same or identical operations, and will not be described in detail below. The same holds true for the control steps shown in FIGS. 9 and 10.

The first image capturing sequence is basically the same as the image capturing sequence of the image capturing system 10 shown in FIG. 6 except that step S8 a is carried out instead of step S8 shown in FIG. 6.

Since the RIS 29 is not connected to the image capturing system 10 a, the image capturing system 10 a is unable to acquire ordering information about the number of times that the patient 14 is to be imaged (the number of radiographic images thereof to be captured, the number of times that the patient 14 is to be exposed to the radiation X). In step S8 a, it is determined whether the application of the radiation X by the image capturing apparatus 22 is finished or not, e.g., whether the image capturing switch 72 is turned off or not.

If it is judged that the application of the radiation X is finished (“YES” in step S8 a), then information indicating that the image capturing switch 72 is turned off is supplied to the charging controller 108 under the control of the console 28. In step S9, the end-of-A/D-conversion determining unit 107 determines whether the A/D conversion of all the radiographic image information obtained in the present image capturing process is finished or not.

According to the first image capturing sequence of the image capturing system 10 a, if it is judged that the application of the radiation X is finished (“YES” in step S8 a) and the A/D conversion is finished (“YES” in step S9), then the charging controller 108 generates a feeding permission signal in step S10. Therefore, even though the number of times that the patient 14 is to be imaged is not acquired from the RIS 29, the end of the capturing of the desired number of radiographic images can be judged from the stop of the application of the radiation X, e.g., the turning-off of the image capturing switch 72. Accordingly, noise caused by the contactless (wireless) power feeding from the power feeder 25 is prevented from adversely affecting the analog radiographic image information, and the image capturing system 10 a can quickly start (resume) supplying electric power to the battery 44 after the A/D conversion, in response to the feeding permission signal from the charging controller 108.

A second image capturing sequence of the image capturing system 10 a will be described below with reference to FIG. 9. The second image capturing sequence includes steps S8 b, S9 b instead of steps S8 a, S9 of the first image capturing sequence shown in FIG. 8.

In step S8 b shown in FIG. 9, the end-of-A/D-conversion determining unit 107 determines whether the A/D conversion of radiographic image information by the A/D converter 70 is ended or not, as with steps S9 shown in FIGS. 6 and 8. Then, if it is judged that the A/D conversion is finished (“YES” in step S8 b), then control goes to step S9 b.

In step S9 b, the charging controller 108 determines whether a given time (constant time) has elapsed after the end of the A/D conversion or not. If it is judged that the given time has elapsed after the end of the A/D conversion (“YES” in step S9 b), then the charging controller 108 generates a feeding permission signal in step S10. Since the elapse of the given time after the end of the A/D conversion is determined in step S9 b, a data transfer time (saving time) is secured for transferring the digital radiographic image information to the image memory 100. In other words, the charging controller 108 generates a feeding permission signal after the data transfer time has elapsed. Consequently, noise due to the power feeding is effectively prevented from adversely affecting the image data being transferred to the image memory 100.

A third image capturing sequence of the image capturing system 10 a will be described below with reference to FIG. 10. The third image capturing sequence includes step S7 c instead of steps S7, S8 a, S9 of the first image capturing sequence shown in FIG. 8.

In step S7 c shown in FIG. 10, it is determined whether a given time (constant time) has elapsed after the image capturing apparatus 22 has started to capture a radiographic image, i.e., after the radiation X has started being applied, or not. The given time may start being measured from a time at which the image capturing switch 72 (the second stage referred to above) is operated or a time at which the radiation detector 40 starts detecting the radiation X, for example.

If it is judged that the given time has elapsed after the image capturing apparatus 22 has started to capture a radiographic image (“YES” in step S7 c), then the charging controller 108 generates a feeding permission signal in step S10. Consequently, the contactless (wireless) power feeding is prevented from being performed during the storage period, the readout period, the A/D conversion period, as referred to above, and also during the data transfer time (saving time) for transferring the digital radiographic image information to the image memory 100. Therefore, noise due to the contactless (wireless) power feeding is effectively prevented from adversely affecting the image data being transferred to the image memory 100. In this case, the end-of-A/D-conversion determining unit 107 may judge that the A/D conversion is finished in view of the given time from the start of the application of the radiation X. Thus, the function of the end-of-A/D-conversion determining unit 107 may be integrated into the charging controller 108.

With the image capturing system 10 a, as with the image capturing system 10, it is possible to generate the feeding permission signal (step S10) after the radiographic image information has been transmitted from the image memory 100 via the transceivers 48, 116 to the console 28.

If the number of radiographic images to be captured can be set by the console 28, then the image capturing system 10 a may be configured to carry out a control sequence which is the same as the control sequence shown in FIG. 6 in accordance with the set number of radiographic images to be captured.

FIG. 11 is a block diagram of a radiographic image capturing system 10 b according to a first modification of the radiographic image capturing system 10 shown in FIG. 4.

In the radiographic image capturing systems 10, 10 a described above, the end-of-A/D-conversion determining unit 107, the charging controller 108, and the image capturing controller 109 for controlling the inhibition of the power feeding by the power feeder 25 and also controlling the start of the image capturing by the image capturing apparatus 22 are incorporated in the electronic cassette 24. In the radiographic image capturing system 10 b, an end-of-A/D-conversion determining unit 107 a, a charging controller 108 a, and an image capturing controller 109 a are incorporated in the console 28.

In the radiographic image capturing system 10 b, the end-of-A/D-conversion determining unit 107 a judges that the A/D conversion is finished when the digital radiographic image information has been transmitted from the image memory 100 to the console 28, and sends information about the above judgment to the charging controller 108 a and the image capturing controller 109 a, for thereby performing an operation sequence based on the image capturing sequence shown in FIG. 6. The end-of-A/D-conversion determining unit 107, the charging controller 108, and the image capturing controller 109 that are incorporated in the electronic cassette 24 may be disabled under the control of the console 28. Alternatively, the radiographic image capturing system 10 b may employ a simplified electronic cassette which is free of the end-of-A/D-conversion determining unit 107, the charging controller 108, and the image capturing controller 109.

As shown in FIG. 11, an end-of-A/D-conversion determining unit 107 b, a charging controller 108 b, and an image capturing controller 109 b may be provided in the image capturing apparatus 22, in addition to or instead of the end-of-A/D-conversion determining unit 107 a, the charging controller 108 a, and the image capturing controller 109 a, and an end-of-A/D-conversion determining unit 107 c, a charging controller 108 c, and an image capturing controller 109 c may be provided in the power feeder 25. In other words, an end-of-A/D-conversion determining unit, a charging controller, and an image capturing controller may be provided in at least either one of the console 28, the image capturing apparatus 22, the power feeder 25, and the electronic cassette 24 to allow the radiographic image capturing system 10 b to operate in the same manner as the radiographic image capturing systems 10, 10 a. The radiographic image capturing system 10 b may include another dedicated console. If an end-of-A/D-conversion determining unit, a charging controller, and an image capturing controller are provided in each of a plurality of apparatus, then the end-of-A/D-conversion determining unit, the charging controller, and the image capturing controller provided in any one of the apparatus may selectively be used under the control of the console 28, for example, whereas the functions of the end-of-A/D-conversion determining unit, the charging controller, and the image capturing controller provided in the other apparatus may be disabled.

Since the electronic cassette 24 incorporates the end-of-A/D-conversion determining unit 107, the charging controller 108, and the image capturing controller 109, the control function for permitting the power feeding after the A/D conversion may be added to an existing radiographic image capturing system simply by slightly modifying the control program of the console 28.

With the radiographic image capturing systems 10, 10 a, 10 b, radiographic images used in a surgical operation are displayed by the display device 26. However, the radiographic image capturing systems 10, 10 a, 10 b may be used to capture ordinary radiographic images in applications other than surgical operations. Similarly, the electronic cassette 24 is not limited to use in the operating room 12, but may be used in medical examinations or used by doctors when going the rounds in hospitals, for example.

As described in the above explanations of the first embodiment, the power feeder 25 may be of any type insofar as it can supply electric power contactlessly (wirelessly) to the electronic cassette 24. For example, the power feeder 25 may comprise components made of a dielectric material for utilizing an electric field (electric field resonance) rather than the magnetic field (magnetic resonance), rather than the LC resonators 84, 88 and the detecting LC resonators 94, and hence may be other than the resonant wireless power feeder. Stated otherwise, the electric energy supplied from the power feeder 25 to the electronic cassette 24 may be optical energy, thermal energy, or other types of energy.

In the radiographic image capturing systems 10, 10 a, 10 b, the radiation detector 40 housed in the electronic cassette 24 directly converts the dose of the applied radiation X into an electric signal with the photoelectric conversion layer 51. However, the radiographic image capturing systems may employ a radiation detector including a scintillator for converting the applied radiation X into visible light and a solid-state detecting device such as of amorphous silicon (a-Si) or the like for converting the visible light into an electric signal (see Japanese Patent No. 3494683).

Alternatively, the radiographic image capturing systems may employ a light-conversion type radiation detector for acquiring radiographic image information. The light-conversion type radiation detector operates as follows: When radiation is applied to a matrix of solid-state detecting devices, the solid-state detecting devices store an electrostatic latent image depending on the dose of the applied radiation. For reading the stored electrostatic latent image, reading light is applied to the radiation detector, and the generated electric current values are acquired as radiation image information. When erasing light is applied to the radiation detector, radiographic image information representing a residual electrostatic latent image is erased from the radiation detector, which can thus be reused (see Japanese Laid-Open Patent Publication No. 2000-105297).

Signals may be sent and received between the image capturing apparatus 22, the power feeder 25, the display device 26, and the console 28 by way of wired communications. Wireless communications between the electronic cassette 24 and external devices may be optical wireless communications based on infrared rays rather than ordinary radio-wave communications.

FIG. 12 shows in perspective an electronic cassette 500 according to a modification of the electronic cassette 24.

As shown in FIG. 12, the electronic cassette 500 has guide lines 504 drawn on the irradiated surface of a casing 502 as a reference mark for an image capturing area and an image capturing position. Using the guide lines 504, the subject to be imaged, such as the patient 14, can be positioned with respect to the electronic cassette 500 and the range in which the radiation X is to be applied to the electronic cassette 500 can be determined, for thereby recording radiographic image information in an appropriate image capturing area of the electronic cassette 500.

The electronic cassette 500 also has a display unit 506 outside of the image capturing area thereof for displaying various items of information about the electronic cassette 500. Specifically, the display unit 506 displays ID information of the patient 14, whose radiation image is recorded in the electronic cassette 500, the number of times that the electronic cassette 500 has been used, an accumulated exposed dose, the charged state (remaining power level) of the battery 44 housed in the electronic cassette 500, image capturing conditions for radiographic image information, and a positioning image representing the patient 14 positioned with respect to the electronic cassette 500, etc. The radiological technician can confirm the patient 14 based on the ID information displayed on the display unit 506, also confirm in advance that the electronic cassette 500 is in a usable state, position the desired area to be imaged of the patient 14 with respect to the electronic cassette 500 based on the displayed positioning image, and capture optimum radiographic image information in the electronic cassette 500.

The electronic cassette 500 includes a handle 508 to be gripped by the user in order to handle and carry the cassette 500 with ease.

The cassette 500 also preferably has an input terminal 510 for connection to an AC adapter, a USB (Universal Serial Bus) terminal 512, and a card slot 516 for receiving a memory card 514, all provided on a side wall of the casing of the electronic cassette 500.

When the charging function of the battery 44 housed in the electronic cassette 500 is low or when there is not enough time to charge the battery 44, an AC adapter is connected to the input terminal 510 to supply electric power from an external source for thereby making the electronic cassette 500 immediately operable.

The USB terminal 512 or the card slot 516 can be used when the electronic cassette 500 is unable to send and receive information to and from an external device such as the console 28 or the like by way of wireless communications. Specifically, when a USB cable connected to the external device is connected to the USB terminal 512, the cassette 500 can send and receive information to and from the external device by way of wired communications through the USB terminal 512 and the USB cable. Alternatively, the memory card 514 is inserted into the card slot 516 and necessary information from the cassette 500 is recorded into the memory card 514. Thereafter, the memory card 514 is disconnected from the card slot 516 and then connected to the external device to send the information to the external device.

FIG. 13 shows a cradle 518 for receiving the electronic cassette 24 and charging the battery 44 housed in the electronic cassette 24. The cradle 518 should preferably be positioned in the operating room 12 or a desired location in the hospital. The cradle 518 may not only be able to charge the battery 44 with a contactless power feeder, not shown, similar to the above power feeder 25, but also have a wireless or wired communication function to send and receive necessary information to and from an external device, such as the RIS 29, the HIS 33, the console 28, or the like. The information that is sent and received may include radiation image information recorded in the electronic cassette 24 loaded in the cradle 518.

The cradle 518 has a display unit 520 for displaying the charged state of the battery 44 housed in the electronic cassette 24 and necessary information including radiation image information acquired from the electronic cassette 24.

A plurality of cradles 518 may be connected to a network, and charged states of the batteries 44 housed in the electronic cassettes 24 loaded in the respective cradles 518 may be retrieved through the network, so that the user can confirm the locations of any electronic cassettes 24 whose batteries 44 are sufficiently charged, based on the retrieved charged states of the batteries 44.

FIG. 14 is a side elevational view, partly in block form, of a radiographic image capturing system 10 c according to a second modification of the radiographic image capturing system 10 shown in FIG. 4.

The radiographic image capturing systems 10, 10 a, 10 b employ the electronic cassette 24 as a radiation detecting apparatus for detecting the applied radiation X and acquiring radiographic image information. The radiographic image capturing system 10 c shown in FIG. 14 employs, instead of the electronic cassette 24, a radiation detecting apparatus 152 incorporated in an image capturing table 150 for the patient 14 to lie thereon, for capturing a radiographic image of the patient 14 while the patient 14 is lying on the image capturing table 150.

The radiation detecting apparatus 152 is substantially the same in construction as the electronic cassette 24 and incorporates therein the radiation detector 40, the battery 44, the wireless power receiver 49, a controller 46 a, and the transceiver 48, which are housed in a box-shaped casing 154 made of a material that is permeable to the radiation X. The controller 46 a functions in substantially the same fashion as the cassette controller 46 of the electronic cassette 24, and has the end-of-A/D-conversion determining unit 107, the charging controller 108, and the image capturing controller 109.

A longitudinal rail 156 is mounted on a lower surface of the image capturing table 150. The radiation detecting apparatus 152 is movable to a desired position in the directions indicated by the arrow X (horizontal direction) along the rail 156 by a slider mechanism, not shown, mounted on the casing 154. Therefore, the radiation detecting apparatus 152 can be moved horizontally to a desired area to be imaged of the patient 14 lying on the image capturing table 150.

With the radiographic image capturing system 10 c, the radiation detecting apparatus 152 is movable and incorporates the battery 44 and the wireless power receiver 49, as with the electronic cassette 24. Consequently, no power cable needs to be connected to the radiation detecting apparatus 152. The radiation detecting apparatus 152 can be moved smoothly without being limited by the power cable and hence can be handled with ease. As with the radiographic image capturing systems 10, 10 a, 10 b, the radiographic image capturing system 10 c is capable of suitably controlling the contactless (wireless) power feeding from the power feeder 25 to the battery 44 and the image capturing by the image capturing apparatus 22 for thereby acquiring radiographic images of high quality.

As shown in FIG. 14, rollers 158 may be mounted on the lower ends of legs of the image capturing table 150. Therefore, the image capturing table 150 can easily be moved to a desired position. If necessary, the rail 156 may be dispensed with, and the radiation detecting apparatus 152 may be fixed to the image capturing table 150.

FIG. 15 is a side elevational view, partly in block form and cross section, of a radiographic image capturing system 10 d according to a third modification of the radiographic image capturing system 10 shown in FIG. 4.

As with the radiographic image capturing system 10 c, the radiographic image capturing system 10 d does not employ the electronic cassette 24, but includes a radiation detecting apparatus 164 detachably mounted on a vertical post 162 fixed to a floor, not shown, and a wall 160, for capturing a radiographic image of the patient 14 while the patient 14 is upstanding.

The radiation detecting apparatus 164 is substantially the same in construction as the electronic cassette 24 and the radiation detecting apparatus 152 and incorporates therein the radiation detector 40, the battery 44, the wireless power receiver 49, the controller 46 a, and the transceiver 48, which are housed in the box-shaped casing 154 made of a material that is permeable to the radiation X.

The radiation detecting apparatus 164, which functions as an upstanding image capturing table, has a pair of vertically spaced upper and lower hooks 166, 168 on a rear surface thereof which faces the post 162. The post 162 has a mounting recess 170 defined in a side surface thereof which faces the radiation detecting apparatus 164. A pair of vertically spaced upper and lower shafts 172, 174 for engaging the respective hooks 166, 168 are disposed in the mounting recess 170 and extend horizontally in transverse directions (shoulder-width direction) of the patient 14. The lower hook 168 is pivotally supported on a pivot shaft 176 for upward swinging movement about the pivot shaft 176 as indicated by the two-dot-and-dash lines in FIG. 15. The lower hook 168 is normally biased to turn downwardly by a spring mechanism, not shown, to stay in engagement with the lower shaft 174.

Since the hook 168 is swingably movable about the pivot shaft 176, the hooks 166, 168 can easily and reliably be brought into and out of hooking engagement with the respective shafts 172, 174, or in other words, the radiation detecting apparatus 164 can easily and reliably be mounted on and removed from the post 162. The radiation detecting apparatus 164 mounted on the post 162 can be moved vertically in the directions indicated by the arrows Y by a slide mechanism, not shown.

In FIG. 15, frames 178 are fixed to respective transverse ends of the casing 154. The frames 178 are in the form of rods to be gripped by the patient 14 when the patient 14 wants to take or keep a desired image capturing posture with respect to the radiation detecting apparatus 164.

With the image capturing system 10 d, the radiation detecting apparatus 164 is removably mounted on and movable with respect to the post 162, and incorporates the battery 44 and the wireless power receiver 49 as with the electronic cassette 24 and the radiation detecting apparatus 152. Consequently, no power cable needs to be connected to the radiation detecting apparatus 164. The radiation detecting apparatus 164 can be moved and mounted and removed smoothly without being limited by the power cable. As with the radiographic image capturing systems 10, 10 a, 10 b, 10 c, the radiographic image capturing system 10 d is capable of suitably controlling the contactless (wireless) power feeding from the power feeder 25 to the battery 44 and the image capturing by the image capturing apparatus 22 for thereby acquiring radiographic images of high quality.

FIG. 16 is a schematic view of a radiographic image capturing system 10 e according to a fourth modification of the radiographic image capturing system 10, 10 b shown respectively in FIGS. 4, 11.

The radiographic image capturing system 10 e differs from the radiographic image capturing system 10, 10 b (see FIGS. 4 and 10) in that the operation manager 102 has the end-of-A/D-conversion determining unit 107 and the image capturing controller 109, and the console 28, the image capturing apparatus 22 and the power feeder 25 have the charging controllers 108 a, 108 b, 108 c, respectively.

In FIG. 16, constituent elements other than the operation manager 102, the end-of-A/D-conversion determining unit 107, the image capturing controller 109 in the electronic cassette 24, and the charging controllers 108 a, 108 b, 108 c in the console 28, the image capturing apparatus 22 and the power feeder 25 are not illustrated.

In FIG. 16, the console 28, the image capturing apparatus 22 and the power feeder 25 have the charging controllers 108 a, 108 b, 108 c, respectively. However, any one thereof may have a charging controller. That is, in the fourth modification, if the end-of-A/D-conversion determining unit, the image capturing controller and the charging controller are assigned to at least two apparatus (two of the image capturing apparatus 22, the electronic cassette 24, the power feeder 25 and the console 28), the same functions as the operation manager 102 shown in FIG. 5 can be performed. Thus, the fourth modification is not limited to an example of FIG. 16. For example, one apparatus may have only an end-of-A/D-conversion determining unit, while another apparatus may have an image capturing controller and a charging controller.

In the image capturing system 10 e of FIG. 16, the end-of-A/D-conversion determining unit 107 and the image capturing controller 109 of the operation manager 102 recognize a state (operation mode) of the electronic cassette 24, and send a signal corresponding to the state to the charging controllers 108 a, 108 b, 108 c. Then, the charging controllers 108 a, 108 b, 108 c determine the most appropriate power feeding state based on the operation mode (the sent signal), and generates signals corresponding to the determined most appropriate power feeding state.

The image capturing system 10 e according to the fourth modification can obtain the same advantageous effects as the image capturing system 10 of the first embodiment and the image capturing system 10 b of the first modification.

FIG. 17 is a schematic view of a radiographic image capturing system 10 f according to a fifth modification of the radiographic image capturing system 10 shown in FIG. 4.

The image capturing system 10 f differs from the image capturing system 10 (see FIGS. 4 and 5) according to the first embodiment in that the feeding controller 86 of the power feeder 25 has a mutual inductance detecting unit 200, and the wireless power receiver 49 has a relay 202. In FIG. 17, constituent elements other than the LC resonator 84 and the power feeding controller 86 of the power feeder 25, the battery 44 of the electronic cassette 24 and the wireless power receiver 49 are not illustrated.

In an example thereof, the LC resonator 84 of the power feeder 25 comprises an LC parallel resonant circuit having a coil 204 and a capacitor 206 that are connected together in parallel with each other, while the LC resonator 88 or the detecting LC resonator 94 of the electronic cassette 24 comprises an LC parallel resonant circuit having a coil 208 and a capacitor 210 that are connected together in parallel with each other. The relay 202 comprises an operation coil 212 to which the charging controller 108 supplies a signal (electric current), and a contact-type switch 214 for performing ON-OFF action in response to excitation of the operation coil 212 by the electric current. The switch 214 has an end connected to the coil 208 and the capacitor 210, and the other end connected to the charging circuit 90.

When the charging controller 108 determines charging of the battery 44 and then applies electric current to the operation coil 212, the operation coil 212 generates magnetic flux based on the electric current, and magnetizes an electromagnet (not shown). As a result, the electromagnet attracts a piece of iron of the switch 214 to switch from an OFF-state to an ON-state. Thus, contactless power feeding by the power feeder 25 to the battery 44 is enabled. On the other hand, while the contactless power feeding is being performed, the coil 204 of the LC resonator 84 and the coil 208 of the LC resonator 88 or the detecting LC resonator 94 are magnetically-coupled to each other through a mutual inductance mi.

In this state, if the charging controller 108 determines stoppage (inhibition) of charging the battery 44 to stop energization of the operation coil 212, generation of magnetic flux by the operation coil 212 is halted. Accordingly, the piece of iron is separated away from the electromagnet, and the switch 214 is brought into an OFF-state. As a result, the electric connection between the coil 208, the charging circuit 90 and the battery 44 is cut off, and then the mutual inductance mi between the coil 204 and the coil 208 changes abruptly.

The mutual inductance detecting unit 200 detects electric current flowing through the coil 204. When the magnitude of the electric current changes temporally abruptly, the mutual inductance detecting unit 200 judges that the mutual inductance mi has changed abruptly due to switching of the switch 214 from an ON-state to an OFF-state.

When the mutual inductance detecting unit 200 detects an abrupt change of the mutual inductance mi, the feeding controller 86 judges that the charging controller 108 has determined stoppage (inhibition) of charging the battery 44. Then, the feeding controller 86 stops supply of electric energy (high-frequency electric power) to the LC resonator 84.

In the image capturing system 10 f according to the fifth modification, even if the feeding inhibition signal is not supplied for some reasons, the power feeder 25 can stop contactless power feeding based on detection of an abrupt temporal change of the mutual inductance mi by the mutual inductance detecting unit 200, thereby performing feeding control of the battery 44 accurately and reliably. Thus, the power feeder 25 can judge, on its own, whether power feeding to the battery 44 should be inhibited or not, even without supply of the feeding inhibition signal from the charging controller 108.

In the above explanations, if it is judged that the remaining power level of the battery 44 is sufficient, then a feeding inhibition signal and an image capturing permission signal are transmitted to perform charging inhibition control arising from starting of image capturing. When the remaining power level of the battery 44 is sufficient, the following charging inhibition control may be performed instead of the above charging inhibition control. That is, a power switch (not shown) is provided on a side surface of the electronic cassette 24. A doctor 18 or a technician operates the power switch to start image-capturing, and then the image capturing permission signal and the feeding inhibition signal are transmitted to perform charging inhibition control.

With the radiographic image capturing systems 10, 10 a, 10 b, 10 c, 10 d, 10 f, the electronic cassette 24 and the radiation detecting apparatus 152, 164 are movable. Even when the electronic cassette 24 and the radiation detecting apparatus 152, 164 are set in a desired image capturing position, they can easily be supplied with electric power by the power feeder 25. Since the electronic cassette 24 and the radiation detecting apparatus 152, 164 have the end-of-A/D-conversion determining unit, the charging controller, and the image capturing controller, the contactless (wireless) power feeding is not carried out at least until the A/D conversion of the detected radiographic image information is finished. Consequently, it is possible to capture radiographic images of high quality without being adversely affected by noise caused by the contactless (wireless) power feeding, and also to quickly charge the battery 44 while no radiographic images are being captured, i.e., after the image capturing process has been finished.

Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims. 

1. A radiation detecting apparatus comprising: a radiation detector for detecting radiation applied from an external image capturing apparatus and transmitted through a subject; a contactless power receiver for receiving electric power supplied contactlessly from an external contactless power feeder and supplying the received electric power to a power supply; an A/D converter for performing an A/D conversion to convert analog radiographic image information, which has been generated based on the radiation applied to the radiation detector, into digital radiographic image information; an end-of-A/D-conversion determining unit for determining whether the A/D conversion is finished or not; and a charging controller for stopping the contactless power feeder from supplying electric power contactlessly after the external image capturing apparatus has started to capture a radiographic image until the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.
 2. A radiation detecting apparatus according to claim 1, wherein the charging controller generates a feeding inhibition signal to inhibit the contactless power feeder from supplying electric power contactlessly before the external image capturing apparatus starts to capture a radiographic image.
 3. A radiation detecting apparatus according to claim 2, further comprising: an image capturing controller for generating an image capturing permission signal to permit the external image capturing apparatus to capture a radiographic image when the charging controller generates the feeding inhibition signal.
 4. A radiation detecting apparatus according to claim 1, wherein the charging controller generates a feeding permission signal to permit the contactless power feeder to supply electric power contactlessly if the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.
 5. A radiation detecting apparatus according to claim 1, further comprising: an image memory for storing the digital radiographic image information converted by the A/D converter; wherein the end-of-A/D-conversion determining unit judges that the A/D conversion is finished when the digital radiographic image information is stored in the image memory.
 6. A radiographic image capturing system comprising: an image capturing apparatus for applying radiation to a subject; a radiation detecting apparatus including a radiation detector for detecting the radiation transmitted through the subject, an A/D converter for performing an A/D conversion to convert analog radiographic image information, which has been generated based on the radiation applied to the radiation detector, into digital radiographic image information, and a power supply for supplying electric power to the radiation detector; a contactless power feeder disposed in the radiation detecting apparatus, for supplying electric power contactlessly to a contactless power receiver which supplies electric power to the power supply; a controller for controlling the image capturing apparatus, the radiation detecting apparatus, and the contactless power feeder; an end-of-A/D-conversion determining unit for determining whether the A/D conversion is finished or not; and a charging controller for stopping the contactless power feeder from supplying electric power contactlessly after the image capturing apparatus has started to capture a radiographic image until the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.
 7. A radiographic image capturing system according to claim 6, wherein the charging controller generates a feeding inhibition signal to inhibit the contactless power feeder from supplying electric power contactlessly before the image capturing apparatus starts to capture a radiographic image.
 8. A radiographic image capturing system according to claim 7, further comprising: an image capturing controller for generating an image capturing permission signal to permit the image capturing apparatus to capture a radiographic image when the charging controller generates the feeding inhibition signal.
 9. A radiographic image capturing system according to claim 6, wherein the charging controller generates a feeding permission signal to permit the contactless power feeder to supply electric power contactlessly if the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.
 10. A radiographic image capturing system according to claim 9, wherein the charging controller generates the feeding permission signal when the image capturing apparatus stops applying the radiation and when the end-of-A/D-conversion determining unit judges that the A/D conversion is finished.
 11. A radiographic image capturing system according to claim 9, wherein the charging controller generates the feeding permission signal upon elapse of a given time after the end-of-A/D-conversion determining unit has judged that the A/D conversion is finished.
 12. A radiographic image capturing system according to claim 9, wherein the charging controller generates the feeding permission signal upon elapse of a given time after the image capturing apparatus has started applying the radiation.
 13. A radiographic image capturing system according to claim 6, wherein the radiation detecting apparatus further comprises an image memory for storing the digital radiographic image information converted by the A/D converter; and the end-of-A/D-conversion determining unit judges that the A/D conversion is finished when the digital radiographic image information is stored in the image memory.
 14. A radiographic image capturing system according to claim 6, which is connected to an information management system for storing the number of times that the subject is to be imaged; wherein the end-of-A/D-conversion determining unit determines whether the A/D conversion is finished or not after as many radiographic images of the subject as the number of times that the subject is to be imaged which is stored in the information management system have been captured.
 15. A method of capturing a radiographic image of a subject by applying radiation to the subject, detecting the radiation with a radiation detector of a radiation detecting apparatus, and converting the detected radiation into radiographic image information with the radiation detector, comprising the steps of: supplying electric power contactlessly to a power supply of the radiation detecting apparatus; and stopping supplying electric power contactlessly to the power supply after image-capturing by the radiation has been started at least until an A/D conversion of the radiographic image information detected by the radiation detector is finished. 